Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavior: default newest-first ordering, that totals and balances are included per record, and that the call is free (no quota/cost). It says nothing about pagination or result size behavior despite limit/offset existing.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two compact sentences plus a one-word cost signal; the resource and ordering are front-loaded before the filter list. The trailing 'Free.' is terse and useful rather than filler, though the fragmentary style means no sentence explicitly frames the operation.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 9 optional params, no output schema and full annotation coverage, the description supplies the essentials: what is returned, ordering, filterable dimensions, and cost. Pagination behavior is the main gap, but for an unpaginated-optional list call this is close to sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 44%, so the description must carry weight; it does explain which dimensions are filterable (kind, status with the overdue/unpaid/expired nuance, customer, issue date) and adds the 'newest first' orientation. It leaves limit, offset, company_id and contact_id unmentioned, and the status detail largely restates the schema's own enum description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the exact resource set (quotes, invoices, credit notes) and the ordering (newest first), which lets an agent distinguish this from write-oriented siblings like invoices_create or invoices_get. It never uses an explicit verb such as 'list', but the enumerative phrasing plus 'filtered by...' makes the read-list intent unmistakable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied through the phrase 'filtered by kind, status..., customer and issue date', which signals this is the browse/search entry point for billing documents. However, no sibling is named as an alternative and no when-not condition is given (e.g., use invoices_get for a single document, invoices_list_repeating for recurring ones), so the agent must infer routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.